While 3D printing technology has been responsible for many advances and inventions over the years, it’s not foolproof – some methods don’t produce items with the best material properties, and others result in surfaces that are rough and unclean. The Vienna University of Technology, better known as TU Wien, is responsible for many innovations in 3D printing materials. The university also generated a spin-off company, the startup Cubicure, which developed a new 3D printing technique called hot lithography.

TU Wien has spent years developing 3D printing processes, along with material mixtures that are well-suited for a wide variety of applications. Cubicure is a direct result of this research.

Dr. Robert Gmeiner, CEO of Cubicure, said, “3D printing already plays a key role in the production of prototypes or utility models. But even for all industrial products that are produced in small quantities or have to be tailored to the individual needs of the individual customer – such as components in the medical sector – the high-quality 3D printing offers great opportunities.”

The patented hot lithography process works with the startup’s novel, optimized resins, which combine high surface quality and precision with excellent material properties to solve the issues that can plague other methods.

Hot lithography

For industrial applications, it’s important to have materials with excellent thermo-mechanical properties, like ABS, along with geometrical properties such as low surface roughness that you might see in injection molded parts.

SLA processes that use light to cure liquid resin are good for 3D printing parts with high surface quality, but the traditional materials for this, such as photopolymers, are brittle and have a low heat distortion temperature.

As Professor Jürgen Stampfl from the Institute of Materials Science and Materials Technology explains, “However, these stereolithography processes often have the problem that the materials traditionally used for them are quite brittle, have rather poor impact resistance and do not hold their shape well at high temperatures.”

High-performance plastic parts from Cubicure.

Cubicure’s new photopolymers are much tougher, with a high dimensional stability under heat. These properties are achieved by using very viscous raw materials, which most commercial SLA 3D printers cannot successfully process. The startup’s hot lithography method can easily process highly viscous specialty resins, as it takes place at temperatures up to 120°C.

“Our technology offers great benefits for many applications. We see great opportunities in automotive, aerospace, electrical and electronics, but also in engineering, precision engineering and the entire supply industry,” said Dr. Markus Pfaffinger, Business Development, Cubicure.

The method uses a high precision laser scanner system to cure the resin, which triggers a chemical reaction that makes the resin harden right where it’s supposed to. Once cooling is complete, the cured resin has improved material properties, able to absorb impacts and shocks without being damaged. The material is strong, with very high surface quality, and heat resistant up to 75°C.

According to the Cubicure website, “Elevated temperatures do not only affect the viscosity of a resin, but also its stability and reactivity. Hence, a precise process handling and control is necessary to avoid unintended polymerization and consequently, the degradation of the material. Thus, the temperature of all process elements can be precisely controlled.”

Thanks to the startup’s new hot lithography 3D printing process, technically relevant plastics can be processed with high precision, at resolutions up to 10 μm – roughly 1/6 the thickness of a single human hair.

Caligma 200 3D printer

Cubicure has not only developed high-viscosity specialty 3D printing resins, but also the Caligma 200 3D printer, which uses hot lithography to process the startup’s new materials. The 3D printer, which will be presented for the first time at next month’s Hannover Messe, along with some commercial-grade products, has a build envelope of 200 x 100 x 300 mm, solid construction and high-quality servo actuators, and a heated plate.

Cubicure and its hot lithography technology work well for a number of application-specific development services.

Dr. Pfaffinger said, “Depending on the application, slightly different resin blends are optimal, and we like to work with our customers to select the best mix of material properties for their application.”

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